Face and lips coloration as a fertility signal in women

2019 Fiscal Year Final Research Report

• Project/Area Number: 19K21002
• Project/Area Number (Other): 18H05810 (2018)
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund (2019); Single-year Grants (2018)
• Review Section: 0110:Psychology and related fields
• Research Institution: Kyoto University
• Principal Investigator: RIGAILL LUCIE 京都大学, 霊長類研究所, 特定助教 (40828894)
• Project Period (FY): 2018-08-24 – 2020-03-31
• Keywords: sexual communication / fertility / ovulation / skin coloration / lips / primates / humans

Outline of Final Research Achievements

I found that there is more difference between than within women in cheek and lip coloration. However, lip luminance (how dark or light the skin appears), is a bit more susceptible to intra-cycle variation in the probability of ovulation: around ovulation lips became darker, as seen in other non-human primate species. But the effect is quite small and likely imperceptible -which is not surprising since we may have noticed that about our own species before.Thus, humans could have inherited the biological bases and mechanisms of expression for female red skin colour from a primate ancestor. This doesn’t necessarily imply that lip luminance plays or does not play an active role in concealing ovulation or in mate choice. Investigating the different forms and functions of female red skin colour in human and non-human primates is necessary to better understand their evolution, i.e., to unveil the different socio-ecological constraints on sexual communication and mate choice.

Free Research Field

psychology

Academic Significance and Societal Importance of the Research Achievements

Psychologists have long studied the "red effect": red color enhances a woman attractivity as it suggests fertility. Along with other studies, my results provide empirical support against this hypothesis: red color is unlikely to play a role into mate choice -at least in modern humans.